"It's definitely a long-term trend, not a fad," says Hudson Riehle, senior vice president of the Research and Knowledge Group for the National Restaurant Association. It's a view shared by restaurant rater Tim Zagat, of the Zagat Survey, which has also added food trucks in several cities to its restaurant rating publications.

Not everyone is gung-ho. There have been howls about unfair competition from brick-and-mortar restaurateurs in Chicago, Washington, D.C. and other cities. And it's unclear whether the arrival of new food trucks on New York City's sprawling street vendor scene has had a role in driving up the costs of vendors permits, which now run about $15,000 for a two-year period on the city's black market, about double what they cost a few years ago, says Sean Basinski, director of the Street Vender Project that advocates for the city's 10,000 mobile businesses, about half of which sell food...

In fact, restaurant industry analysts say that rather than bucking the trend, brick and mortar restaurants increasingly are looking to gain market reach and heighten their public profile by putting their own mobile kitchens on the road. And retailers such as Crate + Barrel have hosted food truck nights in their parking lots on the theory that people who come out for the food may come inside to shop, Myrick says.